Acidic cation exchange resin is an important catalyst in reaction processes utilizing phenols and/or substituted phenols. The most commercially important of such processes today is the reaction of phenol with acetone to form bisphenol-A. For instance, see Farnham et al., U.S. Pat. No. 3,242,219.
The acidic cation exchange resins utilized in such processes gradually lose activity. As a result, after a period of time, perhaps 1 or 2 years, the catalyst must either be replaced or regenerated. Two important causes of such loss of activity, either of which can occur, are:
1. Contamination by metal ions, which neutralize the active acid sites; and
2. Fouling with organic tars, which blocks access by the reactants to the active catalyst sites.
The present invention provides a method for regenerating acidic cation exchange resin that has been deactivated by contamination with metallic ions, and/or which has been fouled by phenol-derived organic tars. The method is particularly useful or bisphenol-A process catalyst, but is also useful for regenerating acidic cation exchange resin from other processes wherein the deactivation is caused by fouling with phenol-derived organic tars, and/or by contamination by metallic ions.